Geopaparazzi

I just came across Geopaparazzi and like to point you there.

https://github.com/geopaparazzi/geopaparazzi
https://play.google.com/store/apps/details?id=eu.hydrologis.geopaparazzi

Although not having tested this app so far on my own, we already have an article about it in the OSM wiki:

http://wiki.openstreetmap.org/wiki/Geopaparazzi